Ratchet mechanism for watch-movements.



W. H EBELHARE. RATCHET MECHANISM FOR WATCH MOVEMENTS.

APPLICATION FILED FIBB.2, 1910.

' Patented Sept 27,1910.

WILLIAM HENRY EBELHARE,

OF WAL'lI-IAM,

MASSACHUSETTS, ASSIGNOR TO THE KEYSTONE WATCH CASE COMPANY. OF PHILADELPHIA. PENNSYLVANIA, A COR- PORATION OF PENNSYLVANIA.

RATCHET MECHANISM FOR WATCH-MOVEMENTS.

Application filed February 2, 1910.

Specification of Letters Patent.

Serial No. 541,443.

which locks the ratchet wheel against retrograde movement shall be so constructed and arranged that after it has dropped behind an advancing tooth of the ratchet wheel it shall be capable of receding or movingbackward to a limited extent, the object of this arrangement being to provide for a corresponding backward movement of the ratchet wheel under the influence of the main spring and thereby prevent said spring from being wound so tight as to render it immovable and therefore ineffective to operate the watch mechanism, a result which is liable to occur in case the main spring is not allowed to loosen itself slightly after being tightly wound up.

The present invention, which relates to click mechanisms of the type above referred to, is particularly intended to provide a mechanism of this character which shall be simple in construction, and of such durability V and eiiiciency as to render it suitable for use in high-grade watch movements, and resides in certain features of construction and arrangement which are hereinafter set forth.

In the accompanying drawing :-Figure 1 is a plan View of a portion of a watch move ment showing the ratchet wheel combined with a click mechanism embodying my invention, as preferably constructed; Fig. 2 is a View similar to Fig. 1, but showing the parts in a different position; andFig. 3 is a 'In the drawing, 2 indicates theratchet wheel of the Watch movement and 3 indicates one of the adjacent wheels in the winding train, these wheels being journaled on studs carried by the plate 4 in the usual manner and provided with intermeshing teeth 5 which, in the particular construction illustrated. are of the typeknown at wolfs teeth, although the form of these teeth is not material to the present invention.

to press the terminal portion 8 of the Adjacent to the periphery of the ratchet wheel 2 is located a detent 6 which is pivotally mounted on a fixed pin 7 and extends forward therefrom substantially in the direction in which the adjacent teeth of the ratchet wheel 2 move in winding the watch, said detent being provided at its forward or free end with an inwardly-turned portion 8 adapted to drop between adjacent teeth of the wheel 2.

At its pivot-ed end the detent 6 is slotted substantially in the direction of its length, as at 9, the pivot pin 7 being passed through the slot 9 and into the plate 4., so that the detent is capable of a limited longitudinal movement with respect to said pin, in addition to its pivotal movement, and a spring 10, which is rigidly secured at one end to the plate at, is arranged to bear at its free end against the detent 6 in such manner as said Patented Sept. 27, 1910.

detent toward the ratchet wheel 2. There is also provideda fixed stop to limit the rearward movement of the detent 6, to

which end the rear end portion' of the detentis preferably recessed on its upper face, as at 11, to receive one end of a plate 12 which is rigidly secured to the plate 4:, the vertical shoulder 13 thereby formed on the detent being shaped to bear against andconform to the front edge 14 of the plate 12, as shown in Figs. 1 and 3, when the detent is at the limit of its rearward movement, in which position the front wall of the slot 9 is located slightly ahead of and therefore out of contact with the pivot pin 7.

- As thus constructed, when the watch is wound the teeth of the ratchet wheel 2 move in the direction indicated by the arrow in Fig. 1, and during the initial movement of said wheel 2 the pressure of the spring 10 upon the detent 6 holds the terminal portion 8 of the latter in contact with the tooth rotate the ratchet wheel 2 in the opposite direction, with the result that the rear face of that tooth which is next in advance of the terminal portion 8 of the detent 6 engages said portion 8 and pushes the detent bodily rearward until the shoulder 13' on the detent brings up against the front edge 14: of the plate 12, whereupon the rearward movement of the detent is arrested and said detent acts as a stop to prevent further reverse movement of the ratchet wheel. The engagement of the conforming'surfaces l3 and 14 under the pressure of the I main spring also resists any turning movement of the detent upon its pivot and thus overcomes any possible tendency of the detent to be thrown out of engagement with the ratchet teeth. The reverse movement of the ratchet wheel which has taken place as above de scribed, however, results in loosening the main spring sufliciently to prevent it from becoming bound, thus leaving it effective for;

its intended purpose, and this reverse movement may evidently be given any desired extent by forming the slot 9 and the recess 11 of suitable lengths. 7

It will be observed that the parts of the click mechanism above described are of simple construction and that the play of the spring 10 is slight in proportion to its length, so that the mechanism is very dura: ble as well as positive and eflicient in operation. The various moving parts of the mechanism are located in suitable recesses which are readily cut in the plate 4, and the presence of the plate 12 in the recess 11 serves to completely cover the slot 9, whereby said slot is prevented from accumulating dirt and the detent is prevented from moving away from said plate at, all these parts being so arranged as to be flush with one another on their upper surfaces. The engagement of the stop surfaces 13 and 14 also serves to take up the rearward thrust exerted onthe detent by the ratchet wheel and thus prevents this thrust from being transmitted to the pivot pin 7, so that there is no tendency for this pin to become loosened and a strong and durable construction results.

Since the various parts have but little thickness, the mechanism is well adapted for use in thin Watch movements, as will be evident.

I claim as my invention 1. In a watch movement, the combination with the ratchet Wheel of adetent adapted to engage the teeth. of the same at its free end and provided with a'slot extending substantially-in the direction of the peripheral movement of said Wheel, a fixed pivot pin passing through said slot, a spring arranged to press the free end of the detent into con tact with the teeth of the ratchet .wheehand a fixed stop to arrestthe rearward movewith a stop shoulder, a fixed pivot pin passing through the slot in the detent, a spring arranged to press the free end of the detent into contact with the teeth of the ratchet wheel, and a-plate overlapping the rear end of the detent and providing a stop surface adapted to engage the shoulder on the detent and limit the rearward movement of the latter.

3. In a watch movement, the combination with the ratchet wheel of a detent adapted to engage the teeth of the same at its free end-and provided with a slot extending sub stantially in the direction of its length, the

slotted portion of said detent being recessed on its upper surface, a spring arranged to press the free end of thedetent into contactwith the teeth ofv-the ratchet wheel, a-- fixed plate extendinginto the recess in the detent and overlying the slot therein, and a fixed plivot pin passing through said plateand s 0t.

4, In a watch movement, the combination with the ratchet wheel of a detent adapted to engage the teeth of the same at its free end and provided with a slot extending substantially in the direction of its length, the slotted portion of said detent being recessed on its upper surface, a fixed pivot pin pass;

ing through said slot, 2. spring arranged to press the free end of the detent into contact with the teeth of the ratchet wheel, and a fixed plate extending into the recess in the detent and overlying the slot therein, the

front wall of said recess and the frontedge of said plate providing conforming stop surfaces adapted to prevent rearward and turning movements of the detent.

In testimony whereof, I have hereunto subscribed my name this 31st day of J anu ary, 1910. v

' WILLIAM HENRY EBELHAR-E.

WVitnesses:

JOHN'L. KERNAN, W. B. MEHL. 

